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Why Did the Romans Convert to Christianity, Again?

A reissued classic of early church history corrects modern fallacies about why the Romans converted.

Credit: FredP

The Rise of Christianity: A Sociologist Reconsiders History, Rodney Stark, Princeton University Press

Prince Vladimir I of Kiev is a fratricide, a rapist, a drunk, and a heathen. Still, he has his moments of quiet contemplation. During one such mood, Vladimir begins to question his pagan faith. He sends ten wise men to investigate the four “civilized” religions: Islam, Judaism, Catholicism, and Orthodoxy.  


After some time, they return. Of the Muslims they say: “There is no happiness among them—only sorrow and a dreadful stench.” Of the Catholics: “We beheld no glory there.” But of the Orthodox:  

The Greeks led us to the edifices where they worship their God, and we knew not whether we were in heaven or on earth. For on earth there is no such splendor or such beauty, and we are at a loss how to describe it. We only know that God dwells there among men, and their service is fairer than the ceremonies of other nations. For we cannot forget that beauty. Every man, after tasting something sweet, is afterward unwilling to accept that which is bitter, and therefore we cannot dwell longer here.

Not long after, Vladimir is baptized into the Orthodox Church.  

Now, a cynic might point out that the prince was also courting the Byzantine emperor’s sister Anna at the time. Yet no one can deny that his conversion was sincere. After he and Anna were engaged, Vladimir put away his four other wives and 800 concubines and gave up the binge-drinking, raping, and pillaging. The prince spent his remaining years on earth traveling the country, building churches and monasteries, and standing as godfather at the baptism of countless peasants. 

So began the Christianization of the Slavs. In time, Vladimir would be raised to the altars as St. Vladimir the Great, Equal to the Apostles.


His story is remarkable, but it’s hardly unique. History is full of rulers who convert to Christianity, seemingly for political reasons, and yet find themselves growing truly devout, sometimes fanatically so. There’s Boris I of Bulgaria, Æthelberht of Kent, Clovis I of the Franks, and, of course, Constantine the Great.  

These stories are the stuff of reactionary dreams and progressive nightmares. Funnily enough, both sides take it for granted that this is how Christendom got its start. Left-wing historians have long argued that Christianity was spread principally by cynical tyrants who used the church as a tool of religious terror to cow their subjects. In the last few years, more and more conservatives seem to believe that the masses will never choose Christendom (or Western civilization, or “Judeo-Christian values,” or whatever you want to call it) freely. It must be imposed upon them by a political elite—for their own good, of course. This is the basic assumption that underlies ideologies like Catholic integralism and Christian nationalism.

Now, I love a good theocracy as much as the next guy. The trouble is, neither the liberal left nor the illiberal right knows much about history.  

As Rodney Stark points out in his magnum opus The Rise of Christianity, the church grew at a rate of about 40 percent per decade for the first three centuries. It did so by entirely peaceful means and despite near-constant opposition from the Roman authorities.  

According to Stark, “The projections reveal that Christianity could easily have reached half the population by the middle of the fourth century without miracles or conversion en masse”—or, indeed, help from the state. “As long as nothing changed in the conditions that sustained that forty-percent-a-decade growth rate,” he continues, “Constantine’s conversion would better be seen as a response to the massive exponential wave in progress, not as its cause.”  

Fr. John Strickland, in his book Age of Paradise, put it more snappily: “Christianity did not take over the empire because Constantine converted to it. Constantine converted to it because it was taking over the empire.”

The question is, how? Stark examines the evidence through a sociological lens, and his insights are invaluable not only to historians but to Christian missionaries, conservative activists, and everyone who cherishes Western civilization.

Conventional wisdom holds that the Faith spread first among the poor and especially slaves. This notion helped inspire Nietzsche’s dismissal of Christianity as a “slave revolt in morality.” It has also become a cornerstone of “liberation theology,” a fusion of Christianity and Marxism popular in the Americas. Like most conventional wisdom, it’s wrong. All the evidence, both past and present, suggests that the first converts were middle and upper-middle class, many of whom no doubt “encouraged” their slaves to embrace their new faith.  

Whatever could possess a well-established Roman citizen to join an illegal religious sect? Stark’s answer is fairly simple. The upper classes tend to be better educated, and more educated folks are more likely to adopt radical new religions. This is true even in our own time. According to Stark’s research, over 80 percent of converts to modern cults—Scientology, Wicca, etc.—are college educated. In fact, they’re the most educated religious demographic, surpassing even Jews (76 percent). Meanwhile, only about half of Roman Catholics have attended college. Stark also notes the inordinate popularity of pseudo-religions like Christian Science and Spiritualism among the Victorian elite.  

So while their economic and political status might incline them towards religious conservatism, the Roman elite were in fact the group most likely to embrace the new faith. If anything, the new religion’s “edginess” adds to its appeal.

Now the question becomes, why Christianity? Of all the thousands of weird cults spread throughout Pax Romana, why choose this one? Stark agrees with the contemporary sources, which suggest that the Romans were amazed by these first Christians’ courage and compassion. He cites two Church Fathers, Tertullian and Dionysius, who say that Christians were rapidly developing a reputation for love: love for the sick, the poor, the elderly, widows, orphans, and, not least, one another.  

As Stark points out, this wasn’t a hollow boast. It’s confirmed by pagan sources. No less than Julian the Apostate wrote an open letter to his priests complaining, “I think that when the poor happened to be neglected and overlooked by the priests, the impious Galileans observed this and devoted themselves to benevolence.” Also, “The impious Galileans support not only their own poor, but ours as well. Everyone can see that our people lack aid from us.”  

For this benevolence, Christians were crucified in the streets. They were tied to poles and set on fire to serve as streetlamps. They were fed to lions in the Coliseum for the amusement of all good pagans. What’s more, as Stark pointed out, they remained loyal to the Emperor. True, they wouldn’t offer that pinch of incense to his idols. But even their Scriptures commanded them to “honor the emperor” and warned that “whoever resists the authority resists the ordinance of God.” Their kindness, courage, docility, and even joy in the face of persecution moved thousands of high-minded Romans to repent and accept baptism.

Conventional wisdom holds that Christianity afforded women a higher status than paganism. That, according to Stark, is actually true. Women were the most successful missionaries in the early church. They weren’t afraid to “flirt to convert,” either. On the contrary: St. Monica converted her husband through her holy life. Their son, Augustine, grew up to become the greatest theologian in Christian history.

We should also remember that, as Stark puts it, in ancient Rome “far more babies were born than were allowed to live.” The leading causes of mortality were infanticide followed by abortion. Contraception, sodomy, and homosexuality were all considered socially acceptable. The church, however, forbade all these practices. So while Roman birthrates plummeted overall, Christian birthrates were consistently high. Simply put, they outbred the pagans.

One point Stark emphasizes is that, in those first centuries, the faith spread mostly through interpersonal relationships, what sociologists call “social networks.” Most conversions were not achieved by street evangelists. The most effective proselytizers appealed to their friends and family—those with whom they enjoyed a high-trust relationship. I’m not sure if the Romans thought it was rude to talk religion at the dinner table but, if so, the first Christians didn’t care.  

This is just a snapshot of Rodney Stark’s study of both the historical record and modern sociological data, much of which he compiled himself. The Rise of Christianity sparked a revolution in the study of the early church, inspiring several many more “popular” titles (notably Tom Holland’s Dominion). It offers a useful counterpoint to the polemical histories that have gained popularity on the Right, for instance, The Church of Apostles and Martyrs by Henri Daniel-Rops, which was republished last year by Cluny Media.  A new paperback edition of The Rise of Christianity was long overdue.  To all the folks at Princeton UP, you’re doing God’s work.


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